FIG. 10 shows an arrangement described in Patent literature 1 as an example of prior art of a click mechanism of this kind. In FIG. 10, reference numeral 1 denotes a bearing that supports a rotationally-manipulated shaft of a switch and reference numeral 2 denotes a rotatable plate.
The bearing 1 has an attachment part 1a having an attachment thread formed in the outer perimeter, and a housing part 1b formed integrally with the attachment part 1a at one end of the attachment part 1a. The attachment part 1a has a shaft hole in which the rotationally-manipulated shaft is inserted. The housing part 1b has a recess formed, into which the shaft hole opens. The inner perimeter of the recess has protrusions and depressions 1c formed in the circumferential direction.
The rotatable plate 2 is housed in the housing part 1b, and a recess 2a is formed on the upper surface of the rotatable plate 2. A U-shaped spring 3 is housed and placed in the recess 2a, and short cylindrical click pieces 4 are housed and placed in notches 2b formed in the rotatable plate 2 at the sides opposite to the leg parts of the U-shaped spring 3. The two click pieces 4 are biased in the opposite directions by the leg parts of the spring 3, and in resilient contact with the projections and depressions 1c formed on the housing part 1b. 
The rotationally-manipulated shaft is inserted in a shaft hole 2c of the rotatable plate 2, so that the rotatable plate 2 rotates integrally with the rotationally-manipulated shaft. At this time, the click pieces 4 move along the protrusions and depressions 1c of the housing 1b, thereby producing a click feel.